Data storage medium and read drive thereof

ABSTRACT

In a recordable data storage medium on which property data was recorded after having been modulated and on which data that is decodable by a cryptographic key to be generated from the property data was recorded, the property data was preferably modulated by a different method from that applied to a read-only data storage medium. Then, an optical disc drive, having no ability to distinguish the recordable data storage medium from the read-only data storage medium, cannot read the recordable data storage medium. Consequently, a greater number of drives should be equipped with the function of recognizing the type of a given data storage medium and the copyright protection function should be consolidated.

TECHNICAL FIELD

[0001] The present invention relates to a data storage medium such as anoptical disc, which can be used effectively to guarantee appropriatecopyright protection, and a read drive for use to read the medium.

BACKGROUND ART

[0002] Disk storage media, on which various types of data (orinformation) can be stored, include read-only data storage media andrecordable data storage media.

[0003] Generally speaking, in the past, read-only drives for readingdata that was written on read-only data storage media were popularizedfirst, and then optical disc drives for writing data on recordable datastorage media or reading the data that was written on recordable datastorage media were popularized. Accordingly, to make the recordable datastorage media also readable by the read-only drives, the physicaldimensions (including the diameter and thickness of discs), physicalproperties (such as reflectance) and data recording format of therecordable data storage media were matched with those of the read-onlydata storage media as closely as possible. As a result, however, evencopyrighted data, recorded on a read-only data storage medium, may beeasily copied onto a recordable data storage medium. Thus, the copyrightof such data has often been infringed.

[0004] To avoid this unwanted situation, various techniques ofdiscouraging illegal duplication have been developed and used in thefield of optical discs. Hereinafter, a conventional technique ofdiscouraging such illegal duplication will be described with referenceto FIGS. 1 through 3.

[0005] First, a conventional recordable data storage medium will bedescribed with reference to FIG. 1. Modulated property data 15 isrecorded on a recordable data storage medium 1 during the manufacturingprocess thereof before the storage medium 1 is put on the market. Themodulated property data 15 is obtained by getting property data 4 (i.e.,information unique to each storage medium) modulated by a modulatingsection 16. The property data 4 may be a disc ID, for example.

[0006] A user who bought the recordable data storage medium 1 can writethe data 6 (to be stored in the removable storage medium) on the userarea of the recordable data storage medium 1 or read the data 6 from theuser area by using an optical disc drive.

[0007] Such an apparatus that can write the data on the recordable datastorage medium 1 and/or read the data from the medium 1 (i.e., theoptical disc drive) includes a demodulating section 17 for demodulatingthe modulated property data 15 that was recorded on the recordable datastorage medium 1 and a decrypting section 10 for decrypting encrypteddata 2 that has also been written on the recordable data storage medium1.

[0008] Where the user writes the encrypted data 2 on the recordable datastorage medium 1, the data 6 is converted into the encrypted data 2(e.g., scrambled data) by an encrypting section 7 inside the opticaldisc drive and then written on the recordable data storage medium 1. Themodulated property data 15 that has been recorded in advance on therecordable data storage medium 1 is used for this encryption. Morespecifically, before the data 6 is encrypted, the modulated propertydata 15 is read out from the recordable data storage medium 1 and thendemodulated by the demodulating section 17. Thereafter, the encrypteddata 2 is generated from the data 6 by using the demodulated propertydata 15.

[0009] In reading the data from the recordable data storage medium 1,first, the modulated property data 15 is read and then demodulated intothe property data 4 by the demodulating section 17. Next, the encrypteddata 2 is read from the user data area on the recordable data storagemedium 1 and then transmitted to the decrypting section 10, where theencrypted data 2 is decrypted by using the demodulated property data 4.

[0010] Next, a read-only data storage medium will be described withreference to FIG. 2.

[0011] After encrypted data 2, modulated property data 15 and recordedencryption data 12 have been recorded on a read-only data storage medium14 during the manufacturing process thereof, the read-only data storagemedium 14 is shipped. The modulated property data 15 is obtained bygetting the property data 4 (i.e., information unique to each storagemedium) modulated by the modulating section 16.

[0012] The encrypted data 2 is generated by encrypting the data 6 with acryptographic key. This cryptographic key is generated by usingencryption data 11. The data 6 to be copyrighted is encrypted with thecryptographic key into the encrypted data 2, which is then recorded onthe read-only storage medium 2.

[0013] The encrypted data 2 and the recorded encryption data 12 arerecorded on different areas on the storage medium during themanufacturing process thereof. The modulated property data 15 may not berecorded on the read-only data storage medium 14. In a DVD-ROM, forexample, the recorded encryption data 12 includes cryptographic keyinformation for use in a contents scrambling system (CSS), and theencrypted data 12 is obtained by scrambling the contents of the data 6in accordance with the information.

[0014] A user who bought the read-only data storage medium 14 can decodethe encrypted data 2 by using a regular read drive. The read drive forreading such a read-only data storage medium 14 includes: a demodulatingsection 17 for demodulating the modulated property data 15 that wasrecorded on the read-only data storage medium 14; a decrypting section10 for decrypting the encrypted data 2 that was recorded on therecordable data storage medium 1; a type recognizing section 8 fordetermining whether the storage medium to read is a read-only datastorage medium or a recordable data storage medium; and a switch 13 forprohibiting or allowing the use of the recorded encryption data 12 inaccordance with the result obtained by the type recognizing section 8.

[0015] FIGS. 3(a) through 3(c) are schematic representations showing aphysical difference between the read-only data storage medium and therecordable data storage medium. Specifically, FIG. 3(a) illustratestracks of the read-only data storage medium, FIG. 3(b) illustratesrecording tracks of the recordable data storage medium, and FIG. 3(c)illustrates a broader area including the portion shown in FIG. 3(b).

[0016] On the read-only data storage medium, pits 51 are formed on thedata recording tracks 50 as shown in FIG. 3(a). On the recordable datastorage medium on the other hand, recording marks 53 are formed ongrooves 52 functioning as data recording tracks as shown in FIG. 3(b).As used herein, the “recording marks” 53 are portions of a recordingfilm, of which the properties (e.g., reflectance) have been changedthrough the exposure to a laser beam.

[0017] On a recordable data storage medium such as a DVD-R or a DVD-RW,pits 54 are formed on a land portion between the grooves 52 and thegrooves 52 slightly wind in a regular period and within a predeterminedamplitude as shown in FIG. 3(c). Such winding of the grooves 52 iscalled “wobbling”. No track wobbling like this is observed on anyread-only data storage medium.

[0018] By detecting the groove wobbling such as that shown in FIG. 3(c),the type recognizing section 8 of the read drive can determine whetherthe storage medium to read is a read-only data storage medium or arecordable data storage medium. A detector that may be used as such atype recognizing section 8 is disclosed in U.S. Pat. Nos. 5,459,706 and6,088,307, which are hereby incorporated by reference.

[0019] As shown in FIG. 2, the encrypted data 2, which has been read outfrom the read-only data storage medium 14, is decrypted by thedecrypting section 10 using the recorded encryption data 12. In thiscase, the type recognizing section 8 senses that the data storage mediumbeing read is a read-only data storage medium and turns the switch 13ON. If necessary, the modulated property data 15 is demodulated by thedemodulating section 17 and used.

[0020] Next, it will be described what if one tries to read therecordable data storage medium 1, onto which the encrypted data 2 andthe recorded encryption data 12 were illegally copied as they are fromthe read-only data storage medium 14, by using the read drive.

[0021] In that case, the type recognizing section 8 senses that thestorage medium to read is not a read-only data storage medium and turnsthe switch 13 OFF. As a result, the recorded encryption data 12 is notsupplied to the decrypting section 10 and the encrypted data 2 is notdecoded.

[0022] However, not every read drive includes the type recognizingsection 8. A read drive with no type recognizing section 8 cannotdistinguish recordable data storage media 1 from read-only data storagemedia 14 and cannot stop the decrypting section 10 from performing itsdecrypting operation. As a result, such a read drive reads even the datathat was copied illegally onto a recordable data storage medium 1.

[0023] As is clear from the foregoing description, a read drive with noability to distinguish recordable data storage media from read-only datastorage media reads the encrypted data not just from a read-only datastorage medium or a recordable data storage medium, on which the datawas written legally, but also from a recordable data storage medium ontowhich the encrypted data was illegally copied from a read-only datastorage medium.

[0024] In the field of optical discs, examples of known read-only datastorage media include CD-ROMs and DVD-ROMs while examples of knownrecordable data storage media include CD-Rs, CD-RWs, DVD-Rs, DVD-RWs andDVD-RAMs.

[0025] This illegal duplication problem happens not only in opticaldiscs but also in any other type of data storage media *that areformatted such that read-only and recordable versions thereof are bothreadable by the same read drive

.

[0026] In order to overcome the problems described above, an object ofthe present invention is to provide a recordable data storage medium,from which not a read drive with no ability to distinguish recordableand read-only data storage media but just a read drive that guaranteesappropriate copyright protection can read user data that was encryptedwith property data.

[0027] Another object of the present invention is to provide a readdrive that prohibits the decrypting section from decoding encrypted datathat was illegally copied onto a recordable data storage medium but thatallows it to decode legally copied encrypted data.

DISCLOSURE OF INVENTION

[0028] A recordable data storage medium according to the presentinvention includes an area on which property data, unique to therecordable data storage medium, was recorded and on which user data tobe used by a user will be written after having been encrypted with theproperty data. The user data will be written on the area in the sameformat as a first data format for a read-only data storage medium. Onthe read-only data storage medium, user data to be used by the user waswritten in the first data format and property data, unique to theread-only data storage medium, was recorded in a second data format. Atleast portion of the property data was recorded on the recordable datastorage medium in a third data format that is different from the seconddata format.

[0029] In a preferred embodiment, the at least portion of the propertydata that was recorded in the third data format includes cryptographickey information for use to encrypt the user data.

[0030] In another preferred embodiment, the third data format uses adifferent modulation method from that of the second data format.

[0031] In another preferred embodiment, the modulation method for thethird data format satisfies an inverted polarity relationship withrespect to the modulation method for the second data format.

[0032] In another preferred embodiment, the modulation method for thesecond data format is a method of converting data “O” into channel data“10” and data “1” into channel data “01”, respectively, and themodulation method for the third data format is a method of convertingdata “0” into channel data “01” and data “1” into channel data “10”,respectively.

[0033] In another preferred embodiment, the third data format uses adifferent error correction data format from that of the second dataformat.

[0034] In another preferred embodiment, the error correction data formatof the third data format uses a different generator polynomial from thatof the error correction data format of the second data format.

[0035] In another preferred embodiment, at least portion of the propertydata was recorded on a burst cutting area (BCA).

[0036] An optical disc drive according to the present invention can readuser data from a recordable data storage medium, on which property data,unique to the recordable data storage medium, was recorded and on whichthe user data to be used by a user is writable. The optical disc driveincludes: a type recognizing section for distinguishing the recordabledata storage medium from a read-only data storage medium; and propertydata reading means for selecting one of multiple methods of reading theproperty data in accordance with a result obtained by the typerecognizing section.

[0037] In a preferred embodiment, the read-only data storage medium hasrecorded thereon user data to be used by the user and property data,unique to the read-only data storage medium, in first and second dataformats, respectively. The user data will be written on the recordabledata storage medium in the same first data format as that of theread-only data storage medium and at least portion of the property datawas recorded on the recordable data storage medium in a third dataformat, which is different from the second data format.

[0038] In another preferred embodiment, the optical disc drive uses areading method compatible with the second data format in reading theproperty data of the read-only data storage medium and uses a readingmethod compatible with the third data format in reading the propertydata of the recordable data storage medium.

[0039] In another preferred embodiment, if encrypted user data waswritten on the recordable data storage medium, the optical disc drivedecodes the user data in accordance with the information contained inthe property data that was recorded on the recordable data storagemedium.

[0040] The type recognizing section distinguishes the read-only datastorage medium from the recordable data storage medium by detecting aphysical feature of a given data storage medium.

[0041] The physical feature is wobbling of recording tracks.

[0042] The physical feature is pits that were formed on land portionsbetween recording grooves.

[0043] The user data is decodable with a cryptographic key that has beengenerated from the property data.

[0044] The third data format uses a different modulation method fromthat of the second data format.

[0045] The modulation method for the third data format satisfies aninverted polarity relationship with respect to the modulation method forthe second data format.

[0046] In reading the property data of the read-only storage medium, theproperty data reading means demodulates channel data “10” into data “0”and channel data “01” into data “1”, respectively. On the other hand, inreading the property data of the recordable storage medium, the propertydata reading means demodulates channel data “01” into data “0” andchannel data “10” into data “1”, respectively.

[0047] The third data format uses a different error correction dataformat from that of the second data format.

[0048] The error correction data format of the third data format uses adifferent generator polynomial from that of the error correction dataformat of the second data format.

[0049] The optical disc drive further includes means for encrypting theuser data in accordance with the information contained in the propertydata. The optical disc drive writes the encrypted user data on therecordable data storage medium.

BRIEF DESCRIPTION OF DRAWINGS

[0050]FIG. 1 is a block diagram illustrating the flow of signals in aconventional recordable data storage medium during the manufacturing andplayback stages thereof.

[0051]FIG. 2 is a block diagram illustrating the flow of signals in aread-only data storage medium during the manufacturing and playbackstages thereof.

[0052] FIGS. 3(a) through 3(c) illustrate the physical features of userdata areas in a read-only data storage medium and a recordable datastorage medium.

[0053]FIG. 4 illustrates a portion of a read-only data storage medium(DVD-ROM) and a portion of a recordable data storage medium (DVD-R orDVD-RW).

[0054]FIG. 5 is a perspective view illustrating a portion of a BCA thatmay be used to record property data on a data storage medium.

[0055]FIG. 6 is a block diagram illustrating the flow of signals in arecordable data storage medium according to the present invention duringthe manufacturing, recording and playback stages thereof.

[0056]FIG. 7(a) shows how property data is modulated in a recordabledata storage medium according to the present invention and FIG. 7(b)shows how property data is modulated in a read-only data storage medium,which is compatible with the recordable data storage medium of thepresent invention.

[0057]FIG. 8 is a block diagram illustrating the flow of signals while aread-only data storage medium, which is compatible with the recordabledata storage medium of the present invention, is read by a read driveaccording to the present invention.

[0058]FIG. 9 shows how a write operation is performed on a DVD-R disc,which is used as a recordable data storage medium according to thepresent invention.

[0059]FIG. 10 shows how a read operation is performed on the DVD-R discthat is used as the recordable data storage medium of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0060] Hereinafter, preferred embodiments of the present invention willbe described with reference to the accompanying drawings.

[0061] On a recordable data storage medium according to the presentinvention, property data, unique to the storage medium, is recordedafter having been modulated during the manufacturing process thereof.The property data (or the modulated property data) is recorded on adifferent area from the area on which the user, who bought the storagemedium, will write his or her data. As for a disklike data storagemedium such as that shown in FIG. 4, for example, a “property datarecording area” may be defined within a lead-in area that is locatedinside (i.e., closer to the center of the disc than) the “user datarecording area”.

[0062] The property data may be written in any of various fashions onthe property data recording area. On a recordable data storage mediumcomplying with the DVD-R standard, for example, the property data may bewritten there by forming slits, extending in the disc radial direction,in the reflective film of the storage medium. These slits may be formedby burning off predetermined portions of the reflective film by a lasertrimming technique, for example. For that reason, the property datarecording area is called a “BCA (burst cutting area)”. Those slitsextend in the disc radial direction and are arranged in a disctangential direction.

[0063]FIG. 5 is a partial perspective view illustrating the surface of astorage medium on which a slit 52 was formed in the reflective film 52thereof. A portion of the reflective film 52 including the slit 54 andanother portion of the reflective film 52 including no slits 54 showdifferent reflectances against an incident laser beam. An optical discdrive such as a read-only drive or a read/write drive can read theproperty data by focusing a laser beam on the property data recordingarea of a given storage medium and detecting a variation in theintensity of the reflected light. A method and apparatus of recording adisc ID and other types of property data on a BCA area is described, forexample, in U.S. Pat. No. 6,160,888, which is hereby incorporated byreference.

[0064] In a DVD-R, an organic dye recording film is sandwiched between adisc substrate including guide grooves for tracking thereon and areflective film. User data is recorded on the recording film by formingmarks in the recording film with a laser beam that has been focused ontothe recording film. In a DVD-RW on the other hand, the recording filmthereof is made of a phase-change type recording material.

[0065] The user cannot change the property data, which was recorded on arecordable data storage medium, by using a normal optical disc drive.The property data includes information that is uniquely given to eachstorage medium, e.g., a disc ID. When the user encrypts user data andwrites the encrypted user data on the user data recording area, theproperty data may be used as a cryptographic key, for example. Thisproperty data may also be used to decode the encrypted user data. Theuser data may be written in the same data format on both a read-onlydata storage medium and a recordable data storage medium, to which thepresent invention is applicable.

[0066] Next, FIG. 6 will be referred to. A recordable data storagemedium 1 according to this embodiment is shipped after modulatedproperty data 3 was recorded thereon during the manufacturing processthereof as shown in FIG. 6. The modulated property data 3 is obtained bygetting property data 4 modulated by a modulating section 5 such as anRZ modulator. In this embodiment, the property data 4 is modulated by amodulation method B, which is different from the conventional one. Theconventional modulation method A is the same as the modulation methodthat is adopted in recording modulated property data on a read-only datastorage medium. In contrast, according to this embodiment, the propertydata 4 is modulated by the modulation method B that is different fromthe modulation method A, which is one of the principal features of thepresent invention.

[0067] Hereinafter, the difference between the modulation methods A andB will be described with reference to FIGS. 7(a) and 7(b).

[0068]FIG. 7(a) shows an example in which the property data is recordedby the modulation method A, while FIG. 7(b) shows an example in whichthe property data is recorded by the modulation method B. In FIGS. 7(a)and 7(b), the property data is shown as DATA, which is defined as anarrangement of zeros and ones.

[0069] Before recorded on a storage medium, the property data isconverted into channel data by a phase encoding (PE) modulationtechnique. In the modulation method A, data “0” is converted intochannel data “10” and data “1” is converted into channel data “01”. Inthe modulation method B on the other hand, data “0” is converted intochannel data “01” and data “1” is converted into channel data “10”. Apair of modulation methods that satisfies such a relationship will beherein referred to as “modulation methods satisfying an invertedpolarity relationship”.

[0070] As can be seen, even if original property data contains the sameinformation, the PE-modulated property data may be defined by one of twodifferent strings of channel bits depending on whether the property datais modulated by the modulation method A or the modulation method B. Inother words, the data format of the property data recorded on theread-only data storage medium is different from that of the propertydata recorded on the recordable data storage medium. These channel bitstrings are recorded on the storage media by an RZ method.

[0071] In FIGS. 7(a) and 7(b), the waveform identified by “BCA”represents the property data that has been modulated by a PE-RZmodulating section. In accordance with this waveform, slit-like openingsare formed on portions of the reflective film that are located in theBCA area of the storage medium (see FIGS. 4 and 5). More specifically, alaser trimming process may be carried out such that the Low levelportions of the waveform, representing the modulated property data BCA,correspond to the slits 54 of the reflective film 52 shown in FIG. 5.

[0072] In the illustrated examples, the channel bit data is recorded bythe RZ method, and the widths of the respective slits formed areconstant, typically about 10 μm. It should be noted that any informationother than the property data may be included there.

[0073] According to the present invention, even when the originalproperty data is the same, the modulated version of the property datahas its data format changed depending on whether the property data issubjected to the modulation method A or the modulation method B. Thus, aportion of the storage medium where the modulated property data has beenrecorded (i.e., a portion of the reflective film that is located in theBCA area) may have one of two different physical shapes (or twodifferent slit arrangement patterns). Accordingly, even if the modulatedproperty data that was recorded on the BCA area of a read-only datastorage medium was copied onto the BCA area of a recordable data storagemedium, the contents of the original property data could not bedemodulated from the modulated property data by any method other than ademodulation method A.

[0074] It should be noted that not all of the property data to berecorded on the recordable data storage medium has to be modulated bythe modulation method B. Rather at least portion of the property data tobe recorded there needs to be modulated by a different modulationmethod.

[0075] Next, a read drive for reading the data that was written on therecordable data storage medium of the present invention will bedescribed.

[0076] This read drive includes: a type recognizing section 8 forrecognizing the type of a given storage medium to read as a read-onlydata storage medium or a recordable data storage medium; and ademodulating section 9 for demodulating the modulated property data 3 byselecting either the demodulation method A or the demodulation method Bin accordance with the result obtained by the type recognizing section8. In the other respects, this read drive may have the sameconfiguration as the conventional read drive or read/write drive.

[0077] A read/write drive for writing user data on the recordable datastorage medium of the present invention includes not only various units,each having the same function as the counterpart of the read drive, butalso other known units for use to write the data.

[0078] Next, it will be described how to write encrypted data on arecordable data storage medium by using the read/write drive.

[0079]FIG. 6 will be referred to again. First, the modulated propertydata 3 is demodulated by the demodulating section 9, the output of whichis sent to an encrypting section 7. In this case, since the medium typerecognizing section 8 has sensed that the storage medium that has beeninserted into the read/write drive is a recordable data storage medium,the demodulation method B is used in the demodulating section 9. Theproperty data that has been demodulated by the demodulating section 9 isused to get the data 6 encrypted, and converted into the encrypted data2, by the encrypting section 6.

[0080] Next, it will be described with reference to FIG. 6 again how toread the encrypted data from the recordable data storage medium 2 byusing the read drive or read/write drive of the present invention. Inthis case, in accordance with the result obtained by the typerecognizing section 8, the demodulation method B is also selected foruse in the demodulating section 9. As a result, the modulated propertydata 3 is demodulated by the demodulating section 9 appropriately. Then,the property data 4 demodulated is supplied to the decrypting section 10and used to decrypt the encrypted data 2.

[0081] Next, it will be described what if one tries to read therecordable data storage medium of this preferred embodiment by using aconventional read drive having no ability to recognize the type of thegiven storage medium to read (or whether it is a recordable data storagemedium or not). In that case, the demodulating section can adopt onlythe demodulation method A. Accordingly, the demodulating section cannotappropriately demodulate the modulated property data 3 that wasmodulated by the modulation method B, and cannot decode the encrypteddata 2. Thus, to read the recordable data storage medium of the presentinvention, the read drive must be able to determine whether the givendata storage medium is a read-only data storage medium or a recordabledata storage medium. Then, a greater number of read drives should beequipped with the function of recognizing the type of a given datastorage medium and the copyright protection should be consolidated.

[0082] Next, it will be described with reference to FIG. 8 how to readthe read-only data storage medium 14 with the read drive of the presentinvention.

[0083] The read-only data storage medium is supposed to be manufacturedas already described with reference to FIG. 4 and the descriptionthereof will be omitted herein. On the read-only data storage medium 14,the modulated property data 15, which was modulated by the modulationmethod A, was recorded.

[0084] During the read operation, the type recognizing section 8 sensesthe storage medium to read as a read-only data storage medium, therebyturning the switch 13 ON. Also, since the storage medium to read is aread-only data storage medium, the demodulation method A is selected inaccordance with the result obtained by the type recognizing section 8.As a result, the modulated property data 15 is demodulatedappropriately.

[0085] Next, it will be described what if one tries to read therecordable data storage medium 1 on which the encrypted data 2 and therecorded encryption data 12 were illegally copied as they are from theread-only data storage medium 14. In that case, the type recognizingsection 8 senses that the storage medium to read is not a read-only datastorage medium. Accordingly, the switch 13 is turned OFF and therecorded encryption data 12 is not supplied to the decrypting section10. As a result, the encrypted data 2 cannot be decoded.

[0086] Next, it will be described how to read the recordable datastorage medium, on which user data was written legally, with the readdrive. In that case, the type recognizing section 8 senses that thestorage medium to read is not a read-only data storage medium.Accordingly, the switch 13 is turned OFF and the recorded encryptiondata 12 is not supplied to the decrypting section 10. However, since thestorage medium to read is a recordable data storage medium, thedemodulation method B is selected in accordance with the result obtainedby the type recognizing section 8. As a result, the modulated propertydata 15 is demodulated appropriately. Then, the decrypting section 10can decode the encrypted data 2 by using the modulated property data 15.

[0087] Next, the flow of signals during a read operation being performedon a DVD-R, which is used as a specific exemplary recordable datastorage medium, will be described with reference to FIG. 9. On the DVD-Rdisc 101 shown in FIG. 9, property data 105, which had been modulated bythe modulation method B, was recorded.

[0088] In reading data from the DVD-R disc 101, the flag information103, which was recorded on the user data area 102 of the disc 101, isread out by reading means 106 and the wobbling of the disc 101 isdetected. The output of the reading means 106 is demodulated by aneight-to-sixteen demodulating section 107 and then subjected to errorcorrection processing by an error correcting section 108. Thereafter,the flag information 106 is sent to a system control section 200. Whenthe presence of wobbling on the disc 102 is detected by a wobblingdetector 109, a polarity switching section 110 performs a “polarityswitching” operation.

[0089] By reference to the flag information 103, the system controlsection 200 recognizes the disc 101 as a DVD-R and instructs the readingmeans 106 to read the property data 105. In response, the reading means106 moves from the user data area 102 toward an inner area of the disc101 to read the property data 105. The property data that has been readout in this manner goes through the polarity switching section 110, RZdemodulating section 111 and error correcting section 112 so as to bedemodulated and supplied as a cryptographic key to decrypting section210. The error correcting sections 112 and 107 may be implemented by thesame circuit.

[0090] When the system control section 200 instructs writing user data,the user data (or recording data) is encrypted by an encrypting section120 with the cryptographic key. An error correction code is added by anerror correction code adding section 121 to the encrypted user data,which is then modulated by an eight-to-sixteen modulating section 1200.Thereafter, the user data is written by writing means 123 on the userdata area of the disc 101.

[0091] The reading means 106 is implementable as an optical pickupincluding the writing means 123. The tracking control over the opticalpickup may be turned ON in reading the user data but may be turned OFFin reading the property data from the BCA area.

[0092] Hereinafter, it will be described with reference to FIG. 10 howto read the encrypted user data from the DVD-R.

[0093] First, the flag information 103 that was recorded on the userdata area 102 of the disc 101 is read out by the reading means 106 whilewobbling is detected by the wobbling detector 109. The output of thereading means 106 is processed by the eight-to-sixteen modulatingsection 107 and the error correcting section 108 and then supplied tothe system control section 210.

[0094] When the presence of wobbling on the disc 101 is detected by thewobbling detector, the polarity switching section 110 performs the“polarity switching” operation.

[0095] On detecting, by reference to the flag information 103, that theuser data was encrypted with the property data, the system controlsection 200 instructs the reading means 106 to read out the propertydata 105. The property data 105 that has been read out by the readingmeans 106 is processed by the polarity switching section 110, RZdemodulating section 111 and error correcting section 112 so as to bereproduced. Then, the reproduced property data is demodulated by acryptographic key demodulating section, thereby reading out thecryptographic key. Then, the cryptographic key is supplied to thedecrypting section 210.

[0096] When the system control section 210 instructs reading the userdata, the user data is processed by the eight-to-sixteen demodulatingsection 107, error correcting section 108 and decrypting section 210 soas to be read out. The cryptographic key that has been demodulated fromthe property data is used for decryption.

[0097] If the encrypted data (i.e., user data) that had been recorded ona DVD-ROM disc 101 was illegally copied onto the DVD-R, the propertydata that was used to encrypt the user data does not match the propertydata that was recorded on the DVD-R disc during the manufacturingprocess thereof. Accordingly, the encrypted data that has been copiedonto the user data area 102 cannot be decrypted by reference to theproperty data that has been read out from the DVD-R disc 101. Supposethe property data of the DVD-ROM could be written on the property datarecording area of the DVD-R disc by some way or other. Even so, sincethe property data of the DVD-ROM disc and that of the DVD-R disc weremodulated by mutually different methods, the property data that has beendemodulated by the RZ demodulating section 111 is regarded as an errorby the error correcting section 112. As a result, the cryptographic keydemodulating section fails to demodulate the cryptographic key on theDVD-ROM disc 101. Consequently, the encrypted data cannot be decryptedor decoded.

[0098] Even if a CSS key has been copied from a DVD-ROM disc onto aDVD-R disc, the read drive does not decode the CSS key on sensing thegiven storage medium as a DVD-R through wobbling detection.

[0099] Every read drive that can read the recordable data storage mediumof the present invention has the type recognizing section 8.Accordingly, the switch 13 may be controlled with just a slight increasein cost.

[0100] Also, since the conventional read drive includes a circuit thatcarries out the demodulation method A, the function of selectivelycarrying out the demodulation method A or the demodulation method B isrealizable only by adding an inverter and a selector to the circuit. Inthis manner, the copyright protection can be consolidated with just aslight increase in cost.

[0101] It should be noted that the type recognizing section 8 maydistinguish the recordable data storage medium from the read-only datastorage medium by any method other than the method of detecting thegroove wobbling as shown in FIG. 5(c). For example, a method ofdetecting pits from the lands between the grooves may also be used.

[0102] As described above, according to the present invention, a dataformat for use to read or write property data from/on a read-only datastorage medium is different at least partially from a data format foruse to read or write property data from/on a recordable data storagemedium. In the preferred embodiments described above, these data formatsare distinguished from each other by applying mutually different datamodulating methods thereto. However, the present invention is notlimited to these specific preferred embodiments. For example, the errorcorrection data format for the property data may be different betweenthe read-only and recordable ones. In that case, the generatorpolynomial of the error correction data format may be changed.

[0103] Alternatively, the information specifying the type of theparticular data format, which was actually selected from multiple typesof data formats for the property data and used to record the propertydata, may be written on a track (user data area) of the recordable datastorage medium.

INDUSTRIAL APPLICABILITY

[0104] If user data written on a recordable data storage mediumaccording to the present invention was encrypted with its property data,then a read drive with no ability to distinguish the recordable datastorage medium from a read-only data storage medium cannot decode theuser data. Then, a greater number of read drives should be equipped withthe function of recognizing the type of a given data storage medium andthe copyright protection can be consolidated.

[0105] A read drive according to the present invention cannot readillegally copied encrypted data from a recordable data storage mediumbut can read legally copied encrypted data from the recordable datastorage medium. Thus, as for legally copied materials, the presentinvention is not unbeneficial for the users at all.

1. A recordable data storage medium including an area on which propertydata, unique to the recordable data storage medium, was recorded and onwhich user data to be used by a user will be written after having beenencrypted with the property data, wherein the user data will be writtenon the area in the same format as a first data format for a read-onlydata storage medium, on which user data to be used by the user waswritten in the first data format and on which property data, unique tothe read-only data storage medium, was recorded in a second data format,and wherein at least portion of the property data was recorded on therecordable data storage medium in a third data format that is differentfrom the second data format.
 2. The recordable data storage medium ofclaim 1, wherein the at least portion of the property data that wasrecorded in the third data format includes cryptographic key informationfor use to encrypt the user data.
 3. The recordable data storage mediumof claim 1, wherein the third data format uses a different modulationmethod from that of the second data format.
 4. The recordable datastorage medium of claim 3, wherein the modulation method for the thirddata format satisfies an inverted polarity relationship with respect tothe modulation method for the second data format.
 5. The recordable datastorage medium of claim 4, wherein the modulation method for the seconddata format is a method of converting data “0” into channel data “10”and data “1” into channel data “01 ” respectively, and wherein themodulation method for the third data format is a method of convertingdata “0” into channel data “01” and data “1” into channel data “10”,respectively.
 6. The recordable data storage medium of claim 1, whereinthe third data format uses a different error correction data format fromthat of the second data format.
 7. The recordable data storage medium ofclaim 6, wherein the error correction data format of the third dataformat uses a different generator polynomial from that of the errorcorrection data format of the second data format.
 8. The recordable datastorage medium of one of claims 1 to 6, wherein at least portion of theproperty data was recorded on a burst cutting area (BCA).
 9. An opticaldisc drive for reading user data from a recordable data storage medium,on which property data, unique to the recordable data storage medium,was recorded and on which the user data to be used by a user iswritable, the optical disc drive comprising: a type recognizing sectionfor distinguishing the recordable data storage medium from a read-onlydata storage medium; and property data reading means for selecting oneof multiple methods of reading the property data in accordance with aresult obtained by the type recognizing section.
 10. The optical discdrive of claim 9, wherein the read-only data storage medium has recordedthereon user data to be used by the user and property data, unique tothe read-only data storage medium, in first and second data formats,respectively, and wherein the user data will be written on therecordable data storage medium in the same first data format as that ofthe read-only data storage medium and at least portion of the propertydata was recorded on the recordable data storage medium in a third dataformat, which is different from the second data format.
 11. The opticaldisc drive of claim 10, which uses a reading method compatible with thesecond data format in reading the property data of the read-only datastorage medium and which uses a reading method compatible with the thirddata format in reading the property data of the recordable data storagemedium.
 12. The optical disc drive of one of claims 9 to 11, wherein ifencrypted user data was written on the recordable data storage medium,the optical disc drive decodes the user data in accordance with theinformation contained in the property data that was recorded on therecordable data storage medium.
 13. The optical disc drive of claim 9,wherein the type recognizing section distinguishes the read-only datastorage medium from the recordable data storage medium by detecting aphysical feature of a given data storage medium.
 14. The optical discdrive of claim 13, wherein the physical feature is wobbling of recordingtracks.
 15. The optical disc drive of claim 13, wherein the physicalfeature is pits that were formed on land portions between recordinggrooves.
 16. The optical disc drive of claim 13, wherein the user datais decodable with a cryptographic key that has been generated from theproperty data.
 17. The optical disc drive of claim 13, wherein the thirddata format uses a different modulation method from that of the seconddata format.
 18. The optical disc drive of claim 17, wherein themodulation method for the third data format satisfies an invertedpolarity relationship with respect to the modulation method for thesecond data format.
 19. The optical disc drive of claim 18, wherein inreading the property data of the read-only storage medium, the propertydata reading means demodulates channel data “10” into data “0” andchannel data “01” into data “1”, respectively, while in reading theproperty data of the recordable storage medium, the property datareading means demodulates channel data “01” into data “0” and channeldata “10” into data “1”, respectively.
 20. The optical disc drive ofclaim 10, wherein the third data format uses a different errorcorrection data format from that of the second data format.
 21. Theoptical disc drive of claim 10, wherein the error correction data formatof the third data format uses a different generator polynomial from thatof the error correction data format of the second data format.
 22. Theoptical disc drive of claim 9, further comprising means for encryptingthe user data in accordance with the information contained in theproperty data, wherein the optical disc drive writes the encrypted userdata on the recordable data storage medium.